Rhodium‐Catalyzed Atroposelective Access to Axially Chiral Olefins via C−H Bond Activation and Directing Group Migration.

Axially chiral open‐chain olefins represent an underexplored class of chiral platform. In this report, two classes of tetrasubstituted axially chiral acyclic olefins have been accessed in excellent enantioselectivity and regioselectivity via C−H activation of (hetero)arenes assisted by a migratable directing group en route to coupling with sterically hindered alkynes. The coupling of indoles bearing an N‐aminocarbonyl directing group afforded C–N axially chiral acrylamides with the assistance of a racemic zinc carboxylate additive. DFT studies suggest a β‐nitrogen elimination–reinsertion pathway for the directing group migration. Meanwhile, the employment of N‐phenoxycarboxamide delivered C−C axially chiral enamides via migration of the oxidizing directing group. Experiments suggest that in both cases the (hetero)arene substrate adopts a well‐defined orientation during the C−H activation, which in turn determines the disposition of the alkyne in migratory insertion. Synthetic applications of representative chiral olefins are demonstrated. [ABSTRACT FROM AUTHOR]